Fire damper latch

ABSTRACT

A latch is designed for a fire damper, the blades of which are integrally formed from an imperforate sheet. With a fire damper of this type, when the integral blade sections are held in a retracted, open position by a fusible link, they are in a stressed condition. Consequently, when the fusible link is parted, the blade sections will move quickly across the frame and close the damper without the use of auxiliary springs or other closure devices. The latch for the fire damper engages in intermediate blade section thereof when the damper is closed and thereby holds the blade sections securely in the closed position. The latch is relatively easy to manufacture and low in cost, yet is dependable and positive-acting in operation.

United States Patent [72] Inventor Raymond L. Alley Toledo, Ohio [21] Appl. No 819,243 [22] 'Filed Apr. 25,1969 [45] Patented July 6, 1971 [73] Assignee The American Warming & Ventilating, lnc.

Toledo, Ohio [54] FIRE DAMPER LATCH 7 Claims, 6 Drawing Figs.

[52] US. Cl 292/230, 160/84, 49/7 [51] Int. Cl v. E05c 9/00, E050 3/04 [50] Field of Search 292/230, 238, 231; 160/84, 206, 207, 35-7, 32, 33, 1, 7

5 1 References Cited UNlTED STATES PATENTS 3,341,971 9/1967 Hartman, .lr 49/7 3,485,284 12/1969 Tumeretai'. 3,495,606 2/1970 Phillips ABSTRACT: A latch is designed for a tire damper, the blades of which are integrally formed from an imperforate sheet. With a tire damper of this type, when the integral blade sections are held in a retracted, open position by a fusible link, they are in a stressed condition. Consequently, when the fusible link is parted, the blade sections will move quickly across the frame and close the damper without the use of auxiliary springs or other closure devices. The latch for the fire damper engages in intermediate blade section thereof when the damper is closed and thereby holds the blade sections securely in the closed position. The latch is relatively easy to manufacture and low in cost, yet is dependable and positive-acting in operation.

PATENTED JUL 6i97l SHEET 2 OF 2 3.591; 221

IN VI-ZN'IK 1h: EAYMUNU L. ALLEY ATTys.

FIRE DAMPER LATCH This invention relates to a latch device and particularly to a fire damper latch for holding blade sections thereof securely in a closed position, when closed.

The latch is designed particularly for fire dampers in which blade sections are integrally formed by a sheet of metal which is folded into a plurality of corrugations by bending in opposite directions at spaced, predetermined intervals. When the blade sections are retracted and held at one side of the fire damper frame by a fusible link, the sheet can be in a stressed condition. Consequently, when the blade sections are released, they will expand and extend quickly across the frame to the closed position. Even when the frame is located in a horizontal position, the stress in the metal sheet can be sufficient to cause the blade sections to close without any additional springs or the like.

Particularly with the fire damper used in the horizontal position, latches are helpful to maintain the blade sections in the closed position and prevent them from bouncing partly open. This is also important to prevent subsequent reopening of the blade sections by external forces, such as being hit by a stream of water from a fire hose.

In accordance with the invention, a fire damper latch is pro vided which is effective to engage one of the blade sections when closed and maintain them in the closed position even against the action of external forces. The latch can be gravity operated and also can be designed so that any tendency for the blade sections to open after reaching the closed position will cause the latch to positively move into the latched position. The latch is uncomplicated both in operation and in design, also being easy to manufacture and low in cost, involving few parts. At the same time, the latch performs with utmost reliability.

It is, therefore, a principal object of the invention to provide a latch for a fire damper of the type having integral blade sections, which latch has the advantages outlined above.

Many other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic view in perspective of a horizontally mounted fire damper embodying the invention, shown in an open position;

FIG. 2 is a somewhat schematic view in perspective of the fire damper of FIG. 1, shown in a closed position;

FIG. 3 is an enlarged, fragmentary view in cross section, taken along the line 3-3 of FIG. I;

FIG. 4 is an enlarged, fragmentary view in elevation of the fire damper latch in the latched position; and

FIG. 6 is an end view in elevation of the fire damper latch of FIG. 5.

Referring to the drawings, a fire damper embodying the invention is indicated at It) and is shown in a horizontal position as when mounted in a ceiling of a building, for example. The fire damper 10 includes a frame 12 having side frame members 14 and 26, and end frame members 18 and 10. The side frame members 14 and 16 preferably have inwardly extending flanges 22 and 24 which act as guides and also aid in maintaining the damper reasonably airtight, when closed. Similar flanges are located on the end frame member 18.

An imperforate sheet 26 of metal is curved or folded in opposite directions at spaced, predetermined intervals, as along folds or fold lines 28, to form adjacent integral blade sections 30. These conform generally to conventional blades but are integrally connected at the longitudinal edges by the folds 28.

One edge of the sheet 26 is affixed to the end frame member and specifically to a flange 32 thereof by suitable fasteners 34. With the sheet 26 in the retracted position, as shown in FIGS. 1 and 3, it is retained by suitable chains 36 and angle members 38 connected by a fusible link 40. The angle members 38 cooperate with a cover panel 41 to protect the blade sections from the elements and dirt.

The folds 28 preferably include bulbous portions 42 and adjacent shallow grooves 44 which can be in contact when the blade sections are retracted so as to place the adjacent blade sections 30 in a stressed condition. Even with conventional U- shaped or V-shaped folds, however, the blade sections can be in a stressed condition when retracted. Consequently, when the fusible link 40 is parted, the blade sections 30 spring quickly toward the end frame member 18 and to a closed position, as shown in FIGS. 2 and 41. Even with the fire damper 10 in a horizontal position, this closing action of the blade sections 30 can be quite strong with the end blades or blade sections contacting the end frame member 18 quite hard. Consequently, no additional springs or other closing means are needed whatsoever. This further decreases the cost of the overall damper and further improves its reliability since there are no additional auxiliary closing devices which are subject to possible failure.

When the blade sections 313 spring to the closed position, they have a tendency to bounce back toward a partly open position. Even with this tendency at a minimum, the end blade section may not remain fully closed. Further, with the blades closed, they can be caused to open if engaged by an external force, such as a stream of water from a fire hose or a blast of hot air. Consequently, it is desirable to provide a latch arrangement for the fire damper.

In accordance with the invention, fire damper latches 46 and 48 are employed with the fire damper I0. Basically, each of the latches 46 and 48 includes a supporting member or plate 50 (FIGS. 5 and 6) and a pivoted latch member or bar 52. The supporting plate 50 has a flange 54 which is affixed to the side frame member 14 or to and specifically to the flange 22 thereof. The supporting plate 50 also includes an upright portion 56 from which extends a double-acting stop 58. The stop 58 is effective to limit movement of the latch member 52 in both directions, so as to determine both an open or unlatched position and a closed or latched position thereof.

A pivot member 60, preferably a shoulder bolt, extends through an opening 62 in the upright portion 56 and receives a nut 64 to hold the shoulder bolt in position with the shoulder thereof lying adjacent one side of the upright portion 56.

The latch member 52 has an opening 66 through which the 7 bolt 60 extends with the member spaced from the supporting plate 50 by a suitable spacer sleeve 68. The latch member 52 preferably has a slanted end 70 having an inclined edge at the side toward the retracted position of the blade sections 30. Also, to improve the reliability of the latch member, a projecting tang 72 extends from a shank 74 toward the retracted position of the blade sections 30. An end 76 of the tang 72 is preferably slanted in a direction opposite to the inclined edge of the end 70.

With the latch member 52 in the latched position, the upper end of the shank 74 is adjacent one edge of the stop 58 to prevent movement of the latch member in a clockwise direction, as shown, thereby preventing the blade section 30 which is adjacent the latch member and all of the other blade sections toward the end frame member 18 from moving toward an open position. The lower edge of the tang 72, when the latch member 52 is in the latched position, preferably is slightly above the path of the blade sections 30 so that the lower edge of the tang 72 will not engage the blade sections.

-As the blade sections move toward the closed position, the latch member 52 which normally is in a vertical position, is engaged by the end blade section and swung upwardly to the open or unlatched position at which time, an intermediate portion of the shank 74 engages the lower surface of the stop 58. In this position, the end 76 of the tang 72 is in or close to the upper portion of the path of the blade sections 30 so that after the blade sections hit the end frame member 18 and tend to bounce open, one of the folds 28 will contact the tang 72 and tend to force the latch member 52 toward the latched position, thereby supplementing the force of gravity. This further provides positive latching action and reliability for the latches 46 and 48. The slanted end 70 enables the latch to extend downwardly between two of the blade sections 30, when closed, and at the same time, minimize the possibility that the end 70 will engage one of the folds 28 which would then force a portion of the sheet 26 toward the lower flange 24.

The latches 46 and 48 need not engage any particular one of the intermediate blade sections 30 to efiectively operate. It is only important that the latches engage one of the end blade section a sufficient distance that enough of the blade sections 30 will be located between the latches 46 and 48 and the end frame member 18 to close the space therebetween. Further the latches 46 and 48 need not even engage the same blade section or extend between the same two blade sections. if the blade sections are in a canted position when closed, this does not hamper the effectiveness of the fire damper.

Various modifications of the above-described embodiment of the invention will be apparent to those skilled in the art and it is to be understood that such modifications can be made without departing from the scope of the invention, the embodiment shown and described being primarily for purposes of illustration and not limitation.

I claim:

' 1. A fire damper comprising, in combination, a closure comprising a single sheet of elastic material folded into corrugations to define a plurality of interconnected blades, a frame, means mounting said closure in said frame for movement between a retracted position and a closed position against an end of said frame, said corrugations in said closure biasing said closure toward the closed position, means for releasably holding said closure in the retracted position to allow air passage through said frame, at least one latch member, means mounting said latch member on said frame for pivotal movement, said latch member being pivotally mounted at a point spaced from said frame end for movement between a first position extending into the path of movement of said closure and a second position clear of the path of said closure, said closure pivoting said latch member toward said second position as said closure moves from the retracted position to the closed position, stop means for limiting the pivotal movement of said latch member to between the first and second positions, and means urging said latch member to pivot toward the first position whereby, when said closure is in the closed position, said latch member is urged to a position between two of said blades for preventing movement of said closure toward the retracted position.

2. A fire damper, as defined in claim 1, wherein said means urging said latch member to pivot includes a tang projecting from said latch member in a direction toward the retracted position when said latch member is in said first position said tang engaging a blade to pivot said latch member if said latch member fails to pivot to the first position after said closure moves to the closed position,

3. A fire damper, as defined in claim 1, wherein gravity urges said latch member to pivot.

4. A fire damper, as defined in claim 1, wherein said at least one latch member comprises two latch members mounted on opposite sides of said frame.

5. A fire damper, as defined in claim 4, wherein said two latch members are mounted to be positioned between a different two blades when said closure i in the closed position.

6. A fire damper, as define in claim 1, wherein said means for releasably holding said closure includes a fusable link, and means for releasing said closure when said fusable link melts.

7. A fire damper, as defined in claim 1, wherein said means mounting said latch includes a support attached to said frame, and wherein said stop means comprises a tab projecting from said support to block the path of said latch member when said latch member is at the first and second positions.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5,591,221 Dated July 97 Inventor-(s) Raymond L.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, Line 51, after "in" delete "elevation of the fire damper latch in the latched position; and and insert cross section taken along the line 4- of Fig. 2; Fig. 5 is a further enlarged side view in elevation of the fire damper latch in the latched position; and

Column 1, Line 59, after and" delete "26" and insert l6 Column 1, Line 59, after "and" delete "10" and insert 2O Column 3, Line 6, after "of the" insert sections 50 spaced from the Column 4, Line 2M, after "closure delete "i" and insert is Signed and sealed this 28th day of December 1 971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents 

1. A fire damper comprising, in combination, a closure comprising a single sheet of elastic material folded into corrugations to define a plurality of interconnected blades, a frame, means mounting said closure in said frame for movement between a retracted position and a closed position against an end of said frame, said corrugations in said closure biasing said closure toward the closed position, means for releasably holding said closure in the retracted position to allow air passage through said frame, at least one latch member, means mounting said latch member on said frame for pivotal movement, said latch member being pivotally mounted at a point spaced from said frame end for movement between a first position extending into the path of movement of said closure and a second position clear of the path of said closure, said closure pivoting said latch member toward said second position as said closure moves from the retracted position to the closed position, stop means for limiting the pivotal movement of said latch member to between the first and second positions, and means urging said latch member to pivot toward the first position whereby, when said closure is in the closed position, said latcH member is urged to a position between two of said blades for preventing movement of said closure toward the retracted position.
 2. A fire damper, as defined in claim 1, wherein said means urging said latch member to pivot includes a tang projecting from said latch member in a direction toward the retracted position when said latch member is in said first position said tang engaging a blade to pivot said latch member if said latch member fails to pivot to the first position after said closure moves to the closed position.
 3. A fire damper, as defined in claim 1, wherein gravity urges said latch member to pivot.
 4. A fire damper, as defined in claim 1, wherein said at least one latch member comprises two latch members mounted on opposite sides of said frame.
 5. A fire damper, as defined in claim 4, wherein said two latch members are mounted to be positioned between a different two blades when said closure i in the closed position.
 6. A fire damper, as define in claim 1, wherein said means for releasably holding said closure includes a fusable link, and means for releasing said closure when said fusable link melts.
 7. A fire damper, as defined in claim 1, wherein said means mounting said latch includes a support attached to said frame, and wherein said stop means comprises a tab projecting from said support to block the path of said latch member when said latch member is at the first and second positions. 